The present invention relates to a method for coating the armature of a rotary electric apparatus such as a motor.
In such a rotary electric apparatus, it is necessary, in general, to prevent expansion and compression of a coil inserted into a slot due to centrifugal force generated during high speed rotation of an armature and therefore a device is integrated to a solid and rigid unit by coating the surface thereof with a coating material such as an epoxy resin group bonding agent, etc. Such coating process has been conducted in the following single coating and hardening procedure (FIG. 6). Namely, the coating material is applied for the coating purpose on the coating area such as a coil of a preheated armature and the coating material is then hardened by heat treatment. However, if a coating material of a low viscosity is used, in this method, for impregnation of the coating material into every corner including the narrow areas between the coils and the deep areas of the slot, a considerable part of the coating material to be impregnated drips because it has a low viscosity, resulting in a problem that the coating process does not provide the device with the necessary strength. Meanwhile, utilization of a material having a high viscosity causes a problem in that the coating does not impregnate into the narrow and deep areas of the armature. Therefore, the coating process has been conducted with a coating material having a compromise viscosity.